1. Field of the Invention
The present invention relates to a type of semiconductor chip and its applications or, more specifically, it relates to a type of semiconductor chip and its application circuits.
2. Description of the Related Art
In common power regulator devices, goals behind the design not only include lowering total circuit costs, but also accelerating response speeds of signals and increasing the efficiency of regulating power supplies. Currently, in order to achieve the goal of mediating many different voltage ranges, the size of voltage regulators are rather large and on-chip regulators are not a reality. For a PCB with multiple electrical devices, because different electrical devices have different voltage demands, power supplies of different output voltages are used to correspond to general voltage ranges that are used by the electrical devices. However, this method consumes a rather large amount of energy, increases the difficulty of designing circuits, and also has a rather high cost.
Therefore, to decrease the amount of energy needed, a common method is to use multiple voltage regulators or converters to modify the voltage from a single power supply unit, in accordance to needs of the electrical devices. These voltage regulators or converters allow the voltage that enters each electrical device to correspond to the device's working voltage. For example, FIG. 1 shows a common diagram of an equivalent circuit structure. On the circuit structure, there is a power supply unit 10, and on one side of the power supply unit 10, a voltage regulator or converter 12 is connected. On the other side of the voltage regulator 12, multiple parasitic elements 14 are connected, and the electrical devices 16 (such as chips) that are to be controlled are also connected to the parasitic elements. Voltage regulator 12 can vary the voltage from power supply unit 10 to a specific range that corresponds to the characteristics of electrical devices 16.
More specifically, voltage regulator 12 can take a steady input voltage and regulate the voltage within a specific range according to the needs of different devices (such as chips), and then input the voltage into the devices. With current circuit technology, this method must be carried out by voltage regulators or converters, resistors, capacitors, and inductors constructed on the PCB. Referring to the electrical devices 16 and voltage regulator 12 disclosed in FIG. 1, there are multiple parasitic capacitors, inductors, and resistors in serial or parallel. Therefore, after a power supply voltage is regulated by voltage regulator 12, the power supply voltage still needs to pass through multiple parasitic elements for enabling electrical devices 16. These multiple parasitic elements are spread out over the PCB and within the package of the chip, and therefore cause a decrease in the efficiency at which the voltage is regulated.
Referring to FIG. 2, an example result of circuits of FIG. 1, a graph is shown where output impedance is plotted against load current frequency. As shown on the graph, when the usage frequency of electrical devices 16 is 107 Hz, the corresponding output impedance is 0.025 ohms. However, when the usage frequency of electrical devices is 108.5 Hz, the output impedance quickly increases to 0.3 ohms, showing an obvious disadvantage to this method of voltage regulation.
The circuit diagram shown in FIG. 3 is commonly used in the design of voltage regulator 12, wherein voltage regulator 12 includes a semiconductor chip 1115, and also an inductor 1320′ and a capacitor 1310′ constructed off-chip. Semiconductor chip 1115 includes MOS 1114b′, diode 1114c′, switch controller 1114a′, and voltage feedback device 1112′. Then a power supply inputs into voltage regulator 12, voltage feedback device 1112′ takes a voltage signal and transfers it to switch controller 1114a′. Switch controller 1114a′ then uses this voltage signal to control when MOS 1114b′ is switched on or off, which therefore controls the output voltage.
Another circuit diagram is shown in FIG. 4. This circuit diagram is similar to that of FIG. 3, except that the diode 1114c′ in FIG. 3 is replaced by MOS 1114d′ in FIG. 4. In this circuit, the voltage feedback device 1112′ also takes a voltage signal and transfers it to switch controller 1114a′, which controls when MOS 1114b′ is switched on or off, therefore controlling the output voltage.
Therefore, the greater the number of different types of electrical devices 16 on the PCB, the greater the number of corresponding voltage regulating devices, so that the supply voltages entering the electrical devices 16 will fall in the correct voltage range. However, such circuit design utilizes a large quantity of high cost voltage regulator devices, and the electrical wiring between different voltage regulators 12 must be separated, causing the need for more metal lines and therefore increasing total manufacturing costs. Needless to say, such circuit design is not suitable for use in micro-scale electronic products. In addition, although the use of multiple voltage regulators 12 in place of multiple power supply units 10 can effectively reduce the amount of resources wasted, the large number of voltage regulators 12 used to account for different electrical devices 16 causes circuits on the PCB to become rather complicated. Because signals pass through a complicated arrangement of wiring, the signal response time is naturally longer and cannot be immediate, simultaneously lowering efficiency of power management. Also, the circuit design takes up a large portion of the PCB, which is an inefficient use of circuit routing.
The present invention proposes a semiconductor chip and its application circuit to lessen above mentioned problems.